Appliances and other machines that generate noise are usually provided with acoustical insulation to reduce the levels of emanating sound. The unwanted sound from these machines can be caused both by the mechanical operation of the motor or other mechanical components within the machine and by the vibration of the machine itself. In a residential dwelling, excessive noise may be generated by dishwashers, clothes washers, clothes dryers, refrigerators, freezers, and microwave ovens, which can be annoying to inhabitants of the dwelling.